Dutch Treat pH Strips are used to distinguish between acids and bases. They help you determine your pH measurement without a pH pen. This product gives you a quick way to estimate the pH of a solution without any expensive equipment or pre-calibration. pH strips are small strips of paper coated with a chemical substance that will undergo a reaction when it comes in contact with the liquid being tested. pH strips change color when they come in contact with a solution. The color must be compared with a chart to get a number and determine if the liquid is acidic, basic, or neutral. It is fast, inexpensive, and easy-to-use method of measuring the acidity or alkalinity of a substance.